He is alleged to have helped 10 militants suspected of involvement in the bombing of the USS Cole off the coast of Yemen in October 2000, to escape from Aden prison in April 2003.

Last November, Mr Nassib was the sole survivor of a US missile attack on a car, which killed six suspected al-Qaeda members in eastern Yemen, officials said.

Sayyed Imam Sherif, who was also reportedly captured, founded the Egyptian Islamic Jihad group which al-Qaeda leader Osama Bin Laden's right-hand man, Ayman al-Zawahri, once led, according to the website of Yemen's ruling party, GPC.

Yemen has stepped up its operations against Islamic extremists since the 11 September 2001, attacks on the United States, allowing US forces to enter the country and train with its military.

The crackdown comes amid reports that terrorists are planning attacks in Yemen, where security has been tightened around foreign institutions and government buildings.